Make object follow path and collide with other object
I explored two ways of constraining a physics object to a curve:
1: A physics constraint connected to your rigid body is set to only travel and orient in a straight line.  Animation Nodes and a python script moves and aligns that constraint to your curve every frame.
AN makes a mesh out of the curve then moves and aligns that physics constraint to the curve every frame.  A python script is needed to work around an apparent bug to get the physics object location.
It's a complicated setup.  It works ok on a roller coaster type track.  It may work better with tuning.  It may work on yours.  If you share your blend file, I'll share mine.
2: Simpler, no plugins: A hidden pipe track and ball(s) connected to your object by physics constraints.
Loft your curve with a bevel so that it's a tube mesh curve, with enough detail and room so that the ball travel in it smoothly.  (make a copy of the curve so you can go back to it if needed)
Convert to mesh and a physics object.  The track is passive, mesh collision. no friction, no bounciness.
Connect a constraint and fix it to your object, perhaps below the pipe track.  your object's location should be constrained to the track, If you want your object to turn with the track, make two balls stick them in the pipe and connect them with a fixed physics constraint and connect your physics object.  You can hide this pipe track and balls in your render.  It's more complicated to have the angle matched to the curve in 3 axis.  Perhaps have a rectangle block traveling down a square tube?  Tested briefly, may work for some cases and with tuning, but a ball works so much smoother.
I have not tested or explored this completely but it should give you some ideas.
Edit: Tested 4 connected spheres forming a flat rectangle car, sliding in a square track, seems to travel smoothly and keep orientation.
Edit2: Which is similar to giving a rectangle a collision margin, It makes the corners of the &quot;Box&quot; collision object smooth.  So that's easier to make and edit.